A075349 a(1) = 1; first differences follow the pattern 1,2,2,3,3,3,4,4,4,4,5,5,5,5,5,..., i.e., the next n differences are n.

1, 2, 4, 6, 9, 12, 15, 19, 23, 27, 31, 36, 41, 46, 51, 56, 62, 68, 74, 80, 86, 92, 99, 106, 113, 120, 127, 134, 141, 149, 157, 165, 173, 181, 189, 197, 205, 214, 223, 232, 241, 250, 259, 268, 277, 286, 296, 306, 316, 326, 336, 346, 356, 366, 376, 386, 397, 408

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..10000

Formula

a(n) = A060432(n-1) + 1. - David Wasserman, Jan 16 2005

Mathematica

Accumulate[Join[{1}, Flatten[Table[Table[n, {n}], {n, 12}]]]] (* Harvey P. Dale, Aug 26 2013 *)

Crossrefs

Sequence in context: A157795 A294060 A003066 * A156024 A234363 A194229

Adjacent sequences: A075346 A075347 A075348 * A075350 A075351 A075352

Keyword

nonn

Author

Amarnath Murthy, Sep 19 2002

Extensions

More terms from David Wasserman, Jan 16 2005

Status

approved